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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.table.client.gateway;

import org.apache.flink.table.api.TableSchema;

/**
 * Util methods to format output of "DESCRIBE" DDLs.
 */
public class DescFormatUtil {

	public static final String FIELD_DELIM = "\t";
	public static final String LINE_DELIM = "\n";
	private static final int ALIGNMENT = 20;

	private DescFormatUtil(){}

	// keep in line with TableSchema.toString()
	public static String colDesc(TableSchema tableSchema, String colName) {
		int index = tableSchema.getColumnIndex(colName);
		return " |-- name: " + colName + "\n" +
			" |-- type: " + tableSchema.getFieldType(index).get() + "\n" +
			" |-- isNullable: " + tableSchema.getFieldNullables()[index] + "\n";
	}

	public static void formatNamedValue(String name, String value, StringBuilder builder) {
		builder.append(String.format("%-" + ALIGNMENT + "s", name)).append("\t");
		int colNameLength = ALIGNMENT > name.length() ? ALIGNMENT : name.length();
		indentMultilineValue(value, builder, new int[]{0, colNameLength}, true);
	}

	private static void indentMultilineValue(String value, StringBuilder tableInfo,
											int[] columnWidths, boolean printNull) {
		if (value == null) {
			if (printNull) {
				tableInfo.append(String.format("%-" + ALIGNMENT + "s", value));
			}
			tableInfo.append(LINE_DELIM);
		} else {
			String[] valueSegments = value.split("\n|\r|\r\n");
			tableInfo.append(String.format("%-" + ALIGNMENT + "s", valueSegments[0])).append(LINE_DELIM);
			for (int i = 1; i < valueSegments.length; i++) {
				printPadding(tableInfo, columnWidths);
				tableInfo.append(String.format("%-" + ALIGNMENT + "s", valueSegments[i]))
					.append(LINE_DELIM);
			}
		}
	}

	private static void printPadding(StringBuilder tableInfo, int[] columnWidths) {
		for (int columnWidth : columnWidths) {
			if (columnWidth == 0) {
				tableInfo.append(FIELD_DELIM);
			} else {
				tableInfo.append(String.format("%" + columnWidth + "s" + FIELD_DELIM, ""));
			}
		}
	}
}